It looks like there is a lot of demand for --make/--remove options to vex so I will do those (and that should nearly approach the end of the new features I will

It looks like there is a lot of demand for --make/--remove options to vex so I will do those (and that should nearly approach the end of the new features I will do on vex). Probably good to do some error checking on the arguments to mkvirtualenv and rmvirtualenv (sleepily hitting enter too early, etc.)